Oil testing device



A. G. THOMAS OIL TESTING DEVICE Filed Deo. l5, 1935 Jan. 19, 1937.

Egg.

Jan. 19, 1937. A, G, THOMAS 2,068,476

OIL TESTING` DEVICE Filed Dec. 15', 1955 5 sheets-sheet 2 JS' THOMAS Jan. 19, 1937. A. G. THoMAs oIL TESTING DEVICE Filed Dec, 15, 195s 3 Sheets-Sheet 5 grwwwbofb TH OMA s (foo Patented Jan. 19, 1937 4UNiTl-:D STATES PATENT loI-Flclz A OIL TESTING DEVICE Albert G. Thomas, Lynchburg, Va. Application December 15, 1933, Serial No. 702,599

5 claims. (o1. 88-14) This invention relates to oil testing devices designed particularly vfor ascertaining the degree of tness remaining in used lubricating oil. It employs the principleof the photo-electric cell, determining the degree of contamination throughythe instrumentality oft transmitted or` reflected light.

Devices which test used'foil photo-electrically are known, but the results are frequently spurious inasmuch `as they may be indiscriminate as regards harmless and deleterious light-occluding particles. It is well knownv that new oil after being churned about in the crank case of the engine ofr an automobile for example becomes discolored by the film of used oil clinging to the parts in the crank case remaining from the former charge of oil, and while the new oil a1-v though discolored, is perfectly good, it would show up poorly in an indiscriminate photo-electric test.

,One of the objects of the present invention is to provide apparatus for separating the colloidal from the gross particles and subjecting a concentration of the latter only, to the yphoto-elec*- tric test.

Another object of the invention is to provide means forclassifying the lcolloidalandthe gross particles either mechanically, electrically or by a combination of both agencies. j

Still another object of the invention is to provide for dilution of the oily under test whereby the point of demarcationbetweenlthe colloidal and the larger particles is accentuated and wherein the fluidity of the oil is so increased as to provide ease of travel of the foreign particles through the oil body when selectivelyfattracted', as will appear, and to rid the sediment of 4cil when the test is not to be-contemplated by color or viscosity factors.

A further object of the invention is the provi-V sion of apparatus by means of vwhich portions of lubricating oilmay conveniently be drawn from crank cases of combustion engines for pur'- v i the viscosity of the same.

yOther objects of vthe inventionwill appear as` characters of reference have been used lto designate identical parts; f

Figure 1 is a vertical section through apparatus for withdrawing used lubricating oil .from

the engine crankl case and subjecting it to the sediment test;

Figure 2 is a section taken along the( line 2-2 of Figure 1;' f

Figure 2A is a slightly modified form of th screen shifting mechanism shown in Figure 2;

Figures 3 and 4 are, respectively, cross sectional and plan'views of an alternative form of screen construction whichl may be substituted for the mesh screens shown in any of the illustrated modiflcationsof the invention;

. Figure 5 is a vertical section through'a modified form of the invention in which the oil is diluted before being delivered to the screen;

Figure 6 illustrates another form of the invention in which the screen has the form of an end less belt adaptedto be broughtby step to 'step progress into' the visionofthe photo-electric cell;

Figure '7 isa vertical section through another form of theinvention in which theA endless belt has a light reflected surface;

' Figure 8 `is another modification in which clasp siflcation of the sediment to be tested from the colloidal particles `is accomplished through elec'- tric instrumentality;

Figure 9 is a form of the invention somewhat similar to that shownin Figure 8 rin which the..

classification is assisted by afmagnetic field;

Figure l10 `is a vertical section through a form of -the` invention in 'which selective attractionl of the particles to betested ltoward a focal regionA in the light beam to the photo-electricv cell is ac complished electrically;

Figure 11 is a vertical section through a mod-".

fraction of oil which is diverted toV a trans' parent tray in which the film of oil is main-' the field of` tained at constant thickness in the photo-electric cell;

Figure 13 is a side elevation througha form of the invention 'in' which the concentration ofmolar particles is produced in the peripheral portion of a whirling transparent cell exposed between a source of light and a photo-electric cell; l

Figure 14 is a front view of the rotating cell;

Figure 15 is a vertical section through a forni of the invention in which the sediment to be tested is electrically. diverted from thev main body of oil to the testing cell and by the same electrical instrumentality collected in the field of vision of the photo-electric cell;

Figure 16 is a vertical section through a mod` ifled form of apparatus for concentrating the molar particles to one side lof a column of flowing oil;

partly in section Figure 1'7 is a vertical section through a tined screen for testing the viscosity as well as the contamination by solid particles of used lubricating oil;

Figure 18 is a side elevation illustrating the employment of the tined device shown in Figure 17 by immersion in a body of oil to be tested, followed by its emergence;

Figure 19 is a plan view of a testing device in which the light passing through a iilm of the sediment bearing oil is magnified by a lens the image being projected upon a screen and a portion of the light passing to a photo-electric cell, whereby a. visual image as well as a photoelectric indication of the state of the oil may be obtained;

Figure 20 is a vertical section through a form of the invention in which sediment bearing oil either in its natural state or diluted is presented in the path of a beam of light to a photo-electric cell from a submerged source, the thickness of the film being maintained constant by an overflow;

' Figure 21 is a slight modification of the device shown in Figure 20 in which a mirror is submerged, the light beam being reflected from the mirror to the photo-electric cell;

Figures 22 and 23 are views in detail showing diagrammatically alternative means for creating a lm of oil through which the beam of the photo-electric couple may be passed.

It will be understood that all of the above described gures are more or less diagrammatic.

Referring now in detail to the several figures and rst adverting to that form of the invention shown in Figures 1 and 2, the numeral I represents a can or reservoir constituting a chamber for collecting the oil that has been tested. Situated at the upper part of -the can I are spaced guide members 2 and 3 in which slides a carriage 4 constituted by a plunger rod 5 projecting externally of the can and biased toward an outward position by means of the spring abutting at one end against the can and at the other against a button I or its equivalent'at the end of the plunger rod 5.` The inner end of the plunger rod is secured, within the can, to a ring 8, said ring forms the frame for a screen 9 and diametrically opposite the plunger rod 5 the ring 8 is secured toY a trunnion I adapted to rotate in the slot formed between the guide members 2 and 3, the plunger rod forwardly of said trunnion provided with a rectangular slide I0 adapted to be guided between the guide members 2 and 3 and to positively hold the screen 9 in horizontal position while the said slide is between said guide members. The ring y8 is provided on its upper portion with a lug I I which abuts a stop I2 formed on the can. When the said lug is against the said stop the ring 8 is in horizontal position. The spring 6 exerts a torsional bias upon the plunger rod maintaining the lug II in contact with the stop I2 and preventing the inadvertent overturning of the ring 8 together with the screen 9.

'I'he guide members2 and 3 are provided with alined apertures I3 and I4. A source of illumination such as an electric lamp I5 is beneath the aperture I3 and a photo-electric cell I6 housed ina dark chamber I'I is above the aperture I4. The plunger rod 5 is adapted to be pushed in against the tension of the spring 6 until the ring 8 together with the screen 9 is in alinement with the apertures I3 and I4 so that the beam from the electric light I5 will pass through the screen 9 which may be of metal gauze, lter paper, etc.; and impinge upon the photo-electric cell.

In the back of the space between the guide members 2 and 3 is a switch stern I8 normally pressed inwardly by a spring I9 and which switch member is represented as being grounded as is also one of the terminals of the electric lamp. The switch stem therefore is in electrical continuity with the circuit through the lamp. The switch stem is adapted when pressed outwardly to make contact with a spring terminal 20 connected to the other side of the source of electric energy, thus the circuit through the lamp is completed. When the plunger rod 5 is pushed inwardly to the position in whichthe screen is in alinement with the apertures I3 and I4, the trunnion ID will have pushed the switch stem into contact with the spring terminal and have caused the illumination of the electric light. When the plunger rod is automatically restored to its normal position of repose as shown, the circuit is broken and the light automatically extinguished. 'I'he switch stem I8 serves also as a stop for the trunnion I0 assuring the accurate positioning of the screen 9 rin the path of the light beam of the photo-electric couple.

A tank 2I is structurally associated with the can I and contains a quantity of a diluent fluid such for example as kerosene. Adjacent the tank 2I is a cylinder 22 having a piston 23 adapted to be manually actuated by an external rod 24 having a spring 25 which normally holds the piston in its uppermost position. Preferably, there is air leakage at the point 26 between the piston rod 25 and the top of the cylinder 22. The piston has a check valve 21 opening inwardly when the piston is raised to admit air to the cylinder. The cylinder near its lower portion is provided with an inwardly opening check valve 28 controlling the flow of kerosene to the cylinder through a conduit 29 having a restricted opening 30 near the bottom of the kerosene tank. Thus when the piston 23 automatically lifts under the urge of the spring 25 kerosene and air are taken in simultaneouslythrough the respective check valves, the kerosene partially nlling the cylinder and the upper part of the cylinder beneath the piston being lled with air. An outwardly opening check valve 3I prevents discharge of the contents of the cylinder until the check valve 3| is overcome by the pressure of the contents of the cylinder when the piston rod is manually depressed. A well 32 is provided adjacent the cylinder 22 having an aperture 33 placing said well in communication with the can I. Said aperture is of somewhat smaller diameter than that of the well defining a ledge 34. A spring 35 is positioned in the bottom of the well and supported by the ledge 34.

The well 32 functions as a receiver for a syringe 39, the latter comprising a barrel 36 having a nozzle 3'I and a plunger 38. The syringe 39 seats on the spring 35. The syringe is adapted to be bodily removed from the well to have the nozzle inserted in an aperture leading to the crank case sump of an internal combustion engine and to draw a specimen of oil from the crank case for the purpose of the test. The syringe with the charge of oil is then re-inserted in the well.

It will be observed that the cylinder 22 has a nozzle 40 in alinement with the screen 9 and that the syringe is mounted in an inclined position so that While in its position of repose, the end" of the nozzle 31 "clearsthe ring 8 so that Aif oilshould dripvfrom the end of the nozzle31', it will'notland on the screen. When the plunger of the Asyringe isV pushed infor purpose of fdischarging oil onto the screen, the pushing'pressure is impartedfto the spring. 35 which springbeingA fairlyA light contracts simultaneously with the descent lof the plunger into the barrel ofthe syringe, ,thecontraction of the spring having the eiect -of moving the nozzlerof the syringe axially downward linto al position4 overlying Athe n screen 9 so" that when the pressureup'on the plunger ejects the oil from the syringe it will impinge uponithe screen'Q, I Some of the oil maygo through, but some ofv it will collect in the cup constituted by thescreen 9'and'thev upper part `ofthe'ring 8, or emin, in the interstice's-.of the 3U tained upon the surface of the screen.

screen.` n y t After the screen nas ,beensupplied with oil the piston rod 24 is depressed, opening the check valve 3| and permitting va jetjof kerosene to inipingeupon the lubricating oiliupon the screen 9.` `dilut'es fthe oil on said screen and causes most of it to pass through themeshes of the screenf The screen isof such neness as to permit the colloidal particles to pass through. with the diluted oil but `the largerparticles are re.-

piston rod 25 is pushed inward to its limit"l a vjet of air will follow the jet of kerosene, the .air blowing out all vestigesof Athe diluted oil and leaving only'the deleterious particles on the sur-Al face of the screen.

Next, the plunger '5. is pushed.` inwardly `until thescreen 9 comes into thefpath `of thebearn from the lamp l5'tethephoto-electricceu. The

trunnion `lli closes "the-circuit at the point 20 lighting the lamp. The beam' passes through the, sediment, its intensity being more or less ob scured by the amountofsediment, and its valuev recorded on the dial 4| of thephotofelectric cur- Y rent indicator.

After the test, the is letgloand` will automatically 4move outwardly under the urge ofv the 'spring 5; For cleaning the screen 9 preparatory to anothentest, the' button '|v is turned, inverting the ring 8 togetherwith the screen 9. l 'While itis in inverted position, the piston rod 24 is again pressedsliooting another 'volume ofV kerosene, 'followed I by air, 'throughv the screen washing out all off the sedimentary I` matterT When thebutton' is letl go' the' ring`8 Vwith the screen 9 automatically resumes its original position with the lug against the'stop" il."4

Other means, the equivalentof those `shown in Figures 2 and 2A-maygcbe employedjfor keep'- inglthe ring-8 with'its associated screenxirra horizontal-position. If "desired, 'the 'air' blast may be omitted and likewise the dilutingfluid,

the "test being made for the contaminating mat? t'ervheld in thefoil filling they meshes'of ,the screen, this test including thejcoll'oidal as Well as the larger of the contaminating particles. y

Other devicesvfthan ascreen maybe substif tutedttherefor, Ain this als well as forms ofthe invention yetjto be described.'4 Figures 3 and ,f1 for exarnplegrshow a grid42. inV the form of a dish" having. a corrugated bottoni 43` and in ,the i valleys of the'icorrugations'are slots44. This dish may beniadefof glass yormetal. vThe sedimentary particles are held back by theslots 44 and'if the dishismade Aof.'Inetala,comparativelyy z small proportion of t sedimentv l`will,y create vquite an. obscuratlon of .the "transmitted light.

horizontal position, limiting the rotation off the ring in. one directionf. The recess however is sufficiently extendedon the opposite side of` said hook tofpermitthe hook to rotate through an angle .of 180c permitting'thefring 8, to be overturned for cleansing purposes.;` A torsional` .l

spring |3'l surrounds the rod lvfbeing` xedto the ring l,9 atone end vand to the slideniember |33 vat the other ,andv normally biasesthe Vhook into engagement with` the Wallv of the recess |34.

Thus throughout the range of shifting move--y ment ofthe screen 9, the ksaid screen is held positively in a horizontal position andinadvertv.ent dipping thereofand lthef'spilling ofthe contentswhile vthe screen is in transitfiromrthe the light beam, is prevented. A.

s Referring to that, form of the inventionfshown receivinglposition 'to'. a positionin thepath ofv in Figure 5, the `oil to be tested isdesigned .to be` supplied to the cylinder.45 and to be diluted by.V

meansn of kerosene or its equivalentdrawn from the tankV 46 rby a suction pump,` 41 and delivered to the oil fin the cylinder45 ,by wayy of` a spout 48. The diluent enters thepump 41 by way of aconduit 491 through "a check valve 5 0,..the'concuit asa-.opening 'nearing bottom pfthe `tank ,46; The outlet of` diluted oil ofthe cylinder45 isv controlledJ by a suitable' valve. for Vexample the boiler valve ,5| havingjay wide slot 52 adapted -toregister with "slotsv 53" and 54.' `When the .valve is opened, .oil is dischargedupon thefsrreenl 9.`

Said screen is mounted in,v a 4slidingcarriage y55 having a handle 55,jby means -of which the car-fA riagemay be pushedinto the path of `the iight beam fromA thejel'ectric lairip.y 56 tovv the yphotoelectric unit 51. The,.carriagef55 together with the screen 9` may `be pulled out forrpurpose of cleansing.

The diluted -cii-ijpasses fniy through 4the l screen 9 takingwith it the colloidal particles `andfv1l` Vleavingthe harmful sediment upon ,they screen@A The oil whichpasses through vthe screen 9;.

collects in a bowl 158.'A c c g Figure 6 shows ai form of 'then'invention in which the oil receiving and diluting means v'are quite similar'tothose described 'in connection with Figure'n5,V butinthis instancefthe carriage 55 and screen 9 is substituted by' an endless screen 59 in the formy of av belt, passing `over rollers'or sprockets'oand lil;l lThe upper nightof said'belt passesV in proximity tothe photo'- electric cell whilethe lower flight passes throughy a reservvoirf62 containing a cleaning iluid such as kerosene. The roller6| is provided with ratchet teeth 54 and on'operating handle 65 'mounted izo-axially oftthe'roller 6| is a `pawl 66 adapted ,1

to ride over the teeth 64 in one direction, ,but

to engage said te'ethwhen movedin the opposite directionand thereby'to impartfstep'bf'step partial rotation to the roller`6| and to thefscreen belt. 59.-Stops'f61and'58 are engaged byjthej` handle 65 `ineach of its extremepositions'andv determine a range of angular amplitude which will bring the area of the screen on which the sediment has been deposited to a position beneath the photo-electric cell. The oil which passes through the screen drains `into av discharge conduit |38 from which it is led off to any convenient receptacle,` not shown. Sediment is washed from the screen by the passage of the lower flight of the belt through the body of cleaning fluid in the reservoir 62.' An air` jet from the nozzle 62 facilitates the cleansing process. i

In Figure '1 a slightly modified form of the apparatus described in vconnection with Figure 6 is illustrated in which the screen belt69 may have a light reflective surface produced for example by plating the screen with chromium or the like, or making it of inherently bright material. 'Ihe source of illumination is placed above the belt and light after passing through the film of sediment bearing oil is' reflected to the photo-electric cell. This has the advantage that the `light has passed twicethrough the "nlm of oil thus increasingV the sensitivity of the test. The screen belt may be of Wire mesh, or of paper sothat light is reflected through the sediment remaining after the oil has vpassed through, or it may be solid and the light reflected through the oil film. Instead of an endless belt, the screen may be of a continuous ribbon wound on a reel, drawn out step by step and the used portions successively discarded.

Figure-12 illustrates a form of the invention in which the larger and harmful particles of suspended matter are concentrated in a small fraction of oil by centrifugal force before beingv driven through a belt 16 from the electric motor 11. The casing 14 forms a chamber having the bottom wall 19 thereof preferably sloping to one point, at which point there is an outlet 19 discharging into the dish 1|i. Oil, preferably propy diluted is poured into, the funnel from ence it runs intol the rotating cup 1|. The

` er particles will` be thrown outwardly byv rifugal force climbing the flaring sides of ne cup and overflowing with a portion of the oil. The colloidal particles remain at the center and pass down beingdischarged through the manually operable valve 13 into-the reservoir 9| after the testis finished. y n

The dish 1|) may be provided with a flange 32 as shown providing a constant level for the sediment bearing oil and thus .determining a uniform thickness for the body ofoil through which the beam from the source oi' illumination 59 passes to the photo-electric cell 51.

Figures 13 and 14 illustrate another utilization of centrifugal force in classifying the harmful larger particles and theharmless particles of colloidal size. Betweenthe source of light 56 and the photo-electric cell 51 a centrifuging flask I3 is rotatably mounted, ,the rotating,

means comprising for example, an electric motor.

11 and suitable belt gearing. The flask prefer-Y ably has inlet and ourlet openings 84 and 85,

\respectively, preferably diametrically arranged A83 from the light, only the peripheral portion being exposed to illumination. The flask is filled with the oil to be tested and then rotated. The sedimentary particles fly out under the urge of centrifugal force occupying the exposed band through which the light passes to the photoelectric cell.

It is contemplated that the flask can be readily demounted and flushed by taking off the screw caps so as to prepare it for subsequent testing. The screen 86 is desired 'may be substituted by an annular screen covering the peripheral portion of the flask, but leaving the central portion exposed to thevlight beam. In this case it would be the colloidal particles which would be tested.

Figures 17 and 18 show details appertaining to equivalents of the screen as a receptor for the oil to be tested. Figur 17 shows a. conduit 81 into which oil may be introduced in any suitable manner, said conduit having a flaring portion 88 fromfwhich depend a series of tines 99. Between the tines are small openings 90. Theoil issues from said small openings spreading itself by surface tension across the spaces .between said tines thus making a test possible which includes`viscosity as a factor, also the colloidal particles, the edges of the tines being preferably so shaped as topromote the optimum distribution of the oil film by capillarity or rsurface tension.

Figure 18 shows a simple `tined device 9| adapted to be dipped into a pan 92` of the oil to be tested and to be withdrawn therefrom carryingwith it a film of f oil bridging the spacesbetween the tines. This also is applicable to a test for viscosity as well as contamination. In place ofthevtined device 9|, a simple transparent or translucent platemay 'be dipped into the pan 92so astoacquire a film of oil and then be lifted from saidpan and exposed to the transmission or the' reflection of the light beam of the photo-electric couple.

In Figure 19 a form 'of the invention is disclosed in which a cell 93 including parallelA 93, a lens 95 intervening so that a magnifiedv image of the film of sediment bearing oil in the cell 93 is projected upon the screen 94. to-electric cell 96 may be placed slightly forward of the screen' 94 and receive a portion of the direct rays passing throughthe cell 93. In this manner an observer obtains a visual picture of the state ofthe oil as well as a photo-electric evaluation of the condition of the oil. l

Figures 20 and 21 show simple testing devices employing a tank 91 having an overflow 99 near the top and being supplied with .the oil to be tested by any suitable means exemplified by the funnel, 99. A photo-electric cell 51 is placed above the open top of said tank. In Figure 20, the source 'of illumination is immersed in the tank at a certain determined level Vbelow the constant liquid level determined by the overflow. In Figure 21 a mirror |00 is placed at this determined level. In Figure 20 the beam from the source of illumination to the photo-electric cell. passes by direct transmission through a deter- `minedthickness of thel oil body. In Figure 21 the source of illumination is above the tank 91 and the light is transmitted by reflection to the photo-electric cell, passing through the determined thickness. of oil twice. It will be under- A phostood in all of the figures of the drawings that the photo-electric cell is in each instance designed to be enclosed so as to be protected from extraneous light.

Figures 22'and 23 show means for creating a film of oil through which the testing light beam may be passed and in which not only viscosity, but the density of the colloidal particles as well as those of larger and more deleterious nature may be tested. Figure 22 represents a dish |39 adapted to contain a body of the oil to be tested, into which a rod |40 held horizontally maybe dipped and .then elevated to a distance above the surface of the oil within the dish. In Figure 23, the oil to be tested is sprayed through a flat nozzle |4| forming a descending curtain or film |42 .which when exposed to the beam of the photo-electric couple, enables a test of the colloidal as well asthe larger particles.

In all those forms of the invention which have so far been vdescribed the means for classifying the harmful and the harmless contaminating particles have been purely mechanical. The process of classification may be materially facilitated by electric means either alone or as adjunctive to the mechanical means. Figure 8 shows a form ofthe invention in which a cylinder `is provided with a piston |02 and an external operating rod |03. This piston is normally biased downward by the spring |04. A

rfunnel is provided for supplying used lubricating oil, preferably diluted to the cylinder |00. A spring closed check valve |06 retains the contents in the cylinder |00 until the piston |02 is released and descendsunder the expansion of the spring |04.

'I'he outlet to the cylinder |00 is a' tube |01 of insulation material preferably glass. The lower end of the tube |01 is flared as shown at |08 and beneath it is a ridge |09, one side of which slopes toward the dish ||0 while the other discharges into the reservoir The ridge |09 is so placed that when the column of oil descends the tube |01 the major portion of the oil flows into the reservoir while the minor portion plate ||4 are connected to the terminals of a high potential source of electro-motive force. The polarity may be determined so as tov insure the movement of the particles dishward. Byv

way of example, the screen ||2 is shown as connected to the positive terminal while the plate ||4 is connected to the negative terminal. The screen ||3 is adapted to be grounded or not and is therefore in circuit with the switch ||5. When the oil descends through the tube |01 the particles passing through the screen ||2 become charged by induction. The positive charge will be repelled. When the particles pass through the screen ||3 if the latter be grounded the positive charge will be repelled to the ground. The particles passing down with the oil then have a negative charge. Upon coming into the zone of the negatively charged plate 4 the negatively charged particles will be repelled toward the left as shown in Figure 8, that is to say, into the stream of oil flowing into the dish. The beam from the light source 56 passes through the layer of oil in the dish ||0 into which the contaminating particles have been thus concentrated.

Figure 9 is a variant of that form of the invention shown in Figure 8. Some of the parts which will apply in both instances have been omitted for the sake of brevity. In this form of the invention the glass |01 is surrounded near the top by a ring ||6. Said ring constitutes one terminal of a source of` high potential electricity for example, the vnegative terminal, the other side of the source of high potential being connected to the terminal ||8 which preferably extends adjacent the flared mouth |08. Particles suspended in the oil which passes downward through the glass tube |01 become charged in the electrostatic field between the terminals ||6 and ||8. A grounded screen ||1 is placed in the glass tube |01 adjacent the terminal ||8 so that the positive charge on the suspended particles is dispelled to the ground. A magnet |43 is placed adjacent the mouth |08 creating a magneticfield extending transversely ofthe direction in which the suspended charged particles descend and deflecting them to one side of said flared mouth. In order to determine the direction of said deflection, the polarity of the terminals I6 and |8 may, if necessary, be reversed. A magnet ||8 which may be either electro or permanent is situated below the screen ||1. The dishy ||9 has a ridge |09 similar to that shown in Figure 8 and similarly placed with respect to the mouth of the tube |01, it being understood that the direction of deflection of the suspended particles is so determined as to bring them into that portion of the oil stream cliverted by the ridge |09 into the dish ||9.

Figure 10 shows a formi of the invention in rwhich the oil is sprayed-from the cylinder |20 directly into the dish |2|. The dish is placed in a charged fleld between the negative and positive terminals |22 and |23, respectively, of a high potential electro-motive source. `The light source and photo-electric ycell are vpositioned near one lend of i the dish. 'Ihe negatively charged terminal |22 will attract the charged particles of matter directly under the photoelectric cell with results as previously described. The positive terminal is adapted to `be grounded as shown.

Figure 11 illustrates va form of the invention in which a transparent plate |33 is arranged in an inclined position as shown with its higher end beneath the outlet |34 of the oil receiver |35. A sample of the oil to` be tested is placed in the receiver and diluted by kerosene drawn from f the tank 2| into the pump 41 and discharged past the check valve |36. The oil spreads over the surface of the plate |33 and flows by gravity glass plate and which are connected to the terminals of a high potential electro-motive source. The contaminating partie-ies passing through this field are electrically charged and will be attracted to the surface of the plate |33. The polarity of the rings may be reversed if necessary to obtain the desired direction of attraction. The plate |33 may have a mirror surface.

In Figure 15 is shown a further modication of the invention in which the dish |24 is placed as in former examples beneath the flared end of an insulation tube |01 in such manner that the stream of oil is divided by the ridge, part flowing into th dish |24 and part into the general reservoir |25. In this form of the invention the tube is surrounded by a ring IIB and a charged eld is carried beyond the mouth of the tube and into the dish itself by the positioning of the positive terminal |26 of the high potential electro-motive source in the dish. The charged particles are diverted to the region permeated by the light beam from the lamp 56 in the manner already described.

In Figure 16, the numeral |01 represents the lower end of the tube bearing the same reference character and which has been shown in previous illustrations. One side of the tube is formed with an aperture in which is inserted in Huid-tight relation, a thin metallic'vessel |21 hermetically sealed and in which a vacuum may be maintained. A filament |28 is enclosed in this vessel. A battery |29 may be employed to furnish current for the filament. A plate |30 is arranged outside of the tube |01 opposite the vessel |21, said plate having a positive bias derived from the high potential battery |3I. The vessel |21 is made of thin material in order to permit escape of the electrons. The electrons from the heated lament |28 will be drawn toward the plate |30 andsome of them will strike the contaminating particles in the oil giving these particles negative, charges. They may be diverted by the electro-magnet |32 or by an electro-static eld, not shown.

It is obvious from the numerous examples as herein illustrated and described showing different applications of the inventive principle that the number of ways in which it may be carrled out are beyond comprehension and that the various forms in which I have illustrated the concept of my invention are to be regarded merely as exemplary and not as limiting the scope of the invention. For instance, the lower terminal ||4 of Figure 8 may be a ring as H2, or it may be a plate outside the tube 1. It is Well known that a ne spray causes the particles to become charged. The oil may be sprayed from a nozzle and the resulting charged particles deected in the manner above described.

What I claim is:

1. Apparatus for testing the fitness of used lubricating oil comprising a screen for collecting the larger contaminating particles from said oil while permitting the colloidal particles to lter through, means for freeing the contaminating particles from oil while on said screen comprising a cylinder having its mouth adapted to discharge upon said screen, a plunger in said cylinder, a diluent supply communicating with said cylinder, said cylinder receiving diluting uid upon the suction stroke of said plunger and discharging it upon said screen upon the compression stroke of said plunger, a photoelectric couple, and means for sliding said screen with the contaminating particles from its oil receiving position to a position in the path of the light beam of said photo-electric couple.

2. Apparatus for testing the tness of used lubricating oil comprising a receptacle, a screen slidably mounted adjacent the upper part of said receptacle, means'for receiving a specimen of the oil to be tested and discharging it upon said screen, the fineness of said screen being determined to collect the larger contaminating particles from said oil and to permit the colloidal particles to lter through said screen with said oil into said receptacle, means for freeing the particles on said screen from oil comprising a diluent tank and a pump drawing diluting liquid from said tank and discharging it upon said screen, said pump being provided with a check valve opening to said atmosphere upon the suction stroke of said pump whereby a body of air is drawn in on top of the body of diluting liquid, and discharged upon said screen in sequence to said diluting iiuid, a vphoto-electric couple, and means for sliding said screen from its oil receiving position to a position in the path of the light beam of said photo-electric couple, the latter being of that type including a gage for indicating variations in the current of the photo-electric element.

3. Apparatus for testing lubricating qualities of used oil and comprising: a support, a mesh screen positioned on said support to receive a sample of used oil to be tested and to separate the larger contaminating particles from the smaller and colloidal particles in said sample, a photo-electric couple on said support comprising a' source of illumination and a photoelectric element including a gage for indicating variations in current therethrough, said screen being located in the path of the light beam between said source of illumination and said element.

4. Apparatus for testing the lubricating qualities of used oil comprising: a support, a filter movably mounted on said support in position to receive a sample of the used oil to be tested and for separating the larger contaminating particles therefrom, a photo-electric couple on said support and comprising a source of illumination and a photo-electric element including a gage for indicating variations in current therethrough, and means for moving said filter from its oil receiving position to a position in the path of the light beam between said source of illumination and the photo-electric element.

5. Apparatus for testing the lubricating qualities of used oil comprising: a support, a mesh screen movably mounted on said support in position to receive a sample of the used oil to be tested and for separating the larger contaminating particles therefrom, a photo-electric couple on said support comprising a source of illumination and a photo-electric element including a gage for indicating variations in current therethrough, and means for moving said screen from its oil receiving position to a position in the path of the iight beam between the said source of illumination and the photo-electric element.

ALBERT G. THOMAS. 

